Lymphocyte Response After a Burn Predicts Infection

Abnormal lymphocyte percentage three days after a burn injury is associated with adverse outcomes, including increased risk of infection.

Burns are a major cause of injury in children. At the American Burn Association-certified pediatric burn center at Nationwide Children’s Hospital, clinicians see about 200 admissions a year.

Burns put patients at risk for many complications, especially infections. But diagnosing infection after a moderate-to-large burn injury is challenging, given the massive inflammatory response that follows. Burns cause profound changes in the immune system, including an elevation of the white blood cells and neutrophils and a reduction of the lymphocyte count.

“When we see patients admitted after a major burn, it’s difficult to tell if it is just the normal response to the burn or if there is an infection,” says Rajan Thakkar, MD, a pediatric surgeon and associate medical director of the Burn Program at Nationwide Children’s. “Due to this hyper-inflammatory response, these patients have the same clinical symptoms as infections.”

In a new study published in the Journal of Surgical Research, Dr. Thakkar and colleagues looked at whether recovery of immune response predicted outcomes in pediatric burn patients. Specifically, they evaluated white blood cell, neutrophil and lymphocyte counts, clinical parameters that are obtained routinely upon admission. Typically, these cell counts start to return to normal about 72 hours after a burn injury.

The researchers looked at those three markers of immune response 72 hours post-burn injury in 84 pediatric patients. They found that abnormal lymphocyte numbers were the most predictive of adverse outcomes.

“On the third day after injury, if the lymphocytes were still low, those patients were more likely to have a longer length of stay in the hospital, more days in the ICU and more days on the ventilator,” says Dr. Thakkar. “When we controlled for everything else, patients with an abnormal lymphocyte count after 72 hours were seven times more likely to get an infection.”

This study suggests lymphocyte count may be helpful in identifying patients with increased likelihood of developing complications. These patients could benefit from more aggressive treatment or surveillance strategies.

“We have more studies to do, but the trend suggests we could use lymphocyte count as an early warning sign of patients who might have some type of infection,” says Dr. Thakkar, who is also a principal investigator in the Center for Clinical and Translational Research in The Research Institute at Nationwide Children’s. “It might help alert the practitioner to suspect infection and possibly send cultures earlier or begin antibiotics with these patients.”